(19)
(11) EP 0 427 201 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
11.12.1991 Bulletin 1991/50

(43) Date of publication A2:
15.05.1991 Bulletin 1991/20

(21) Application number: 90121219.1

(22) Date of filing: 06.11.1990
(51) International Patent Classification (IPC)5: H01Q 25/00, H01Q 3/26, H01Q 3/40
(84) Designated Contracting States:
DE FR GB IT

(30) Priority: 08.11.1989 US 434059

(71) Applicant: Hughes Aircraft Company
Los Angeles, California 90080-0028 (US)

(72) Inventors:
  • Murphy, Timothy A.
    Lynwood, WA 98037 (US)
  • Renshaw, Kenneth H.
    Manhatten Beach, CA 90266 (US)

(74) Representative: Grünecker, Kinkeldey, Stockmair & Schwanhäusser Anwaltssozietät 
Maximilianstrasse 58
80538 München
80538 München (DE)


(56) References cited: : 
   
       


    (54) Satellite beam-forming network system having improved beam shaping


    (57) A steerable beam antenna system (24) for use in satellite communication systems and including a main reflector (32) and an antenna array having a plurality of feed elements (50) is disclosed. Additional feed elements (314, 316) are positioned along with the array (116-119) and are used to cancel undesirable side lobes which appear as the beam is steered towards the end portions of a target area (324, 330). The antenna array is positionable at or near at least one focal point of the main reflector (48), and its feed elements can receive microwaves from or transmit microwaves toward the main reflector. A Butler matrix (110) having multiple input ports (310) and multiple outputs (312) is connected to the array of feed elements and substantially performs a spatial discrete Fourier transformation on a generated set of signals to be transmitted which have a predetermined phase relationship between the signals, which is necessary to create the steerable beam. The Butler matrix also can perform an inverse spatial transformation on a set of incoming signals focused on the array by the reflector and received by the feed elements.







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